Street traffic signalling system

• US 3,885,227 A
• Filed: 04/20/1972
• Issued: 05/20/1975
• Est. Priority Date: 04/20/1972
• Status: Expired due to Term

• Current Assignee: Friedrich-Gerhard Moissl
• Original Assignee: Friedrich-Gerhard Moissl
• Inventors: Moissl, Friedrich-Gerhard
• Primary Examiner(s): Claffy, Kathleen H.
• Assistant Examiner(s): Myers, Randall P.
• Application Number:
  US05/245,791
• Time in Patent Office: 1,125 Days
• Field of Search: 340/40,41,42,37,43,31R,44
• US Class Current: 340/916
• CPC Class Codes: G08G 1/07 Controlling traffic signals

Abstract

A street traffic signalling system for automatically effecting respective selectable signalling conditions or phases at an intersection in correspondence to a mutually independent selection with predetermined protective delay periods between predetermined changes in signalling conditions and in which a plurality of traffic signal means or units are employed at a street intersection with a plurality of logical linkages for controlling the individual conditions or phases, each of the latter having a pair of phase responsive switches cooperable with the associated logical linkage and with timing means for controlling such linkage and an associated signal unit, with one of each pair of switches being operative to effect initiation of a signalling condition or phase and operative to effect termination of a then existing signalling condition or phase and the other switch of a pair being operative to determine protective periods of other signal phases in the event of a transition thereto, with the timing means and each pair of switches being operatively connected to the logical linkages associated therewith by respective shunting fields.

Claims

1. A street traffic signalling system having a plurality of mutually independently selectable signal phases for traffic control at an intersection, particularly a traffic-dependent selection, comprising a plurality of traffic signal units, each for a respective traffic direction, means for each signal unit for actuating respective signal lights thereof to provide the respectivE desired phases therefor, timing means having a plurality of timing outputs, a plurality of logical linkages for each selectable signal phase, operatively connecting predetermined timing outputs of said timing means with the cooperable actuating means for such signal phase, for providing respective protective periods prior to actuation of the go light associated therewith, phase-responsive switch means for each respective selectable phase, operative upon selection of such phase to determine the go light thereof to be actuated, and to initiate termination of the signal phase immediately preceding such new phase, and second phase responsive switch means for each respective selectable phase, operatively connected to logical linkages of other signal phases for effecting a selection of the timing outputs and connecting linkages therefor associated with such other signal phases, in the event of a transition from the associated phase to a new phase, whereby a predetermined time period is provided between termination of such immediately preceding signal phase and actuation of the selected go light of the new phase, in dependence upon the said immediately preceding phase so terminated.

2. A system according to claim 1, comprising in further combination, a plurality of connecting fields, the logical linkages associated with a respective signal phase having a connecting field operatively connecting the same with the cooperable first phase-responsive switch means associated therewith, a connecting field connecting such linkages with cooperable second phase-responsive switch means of the signal phases, and a connecting field connecting such linkages with said timing means, whereby operational and timing variations may be effected by changes in connections within the respective connecting fields.

3. A system according to claim 1, wherein the group of logical linkages for a respective signal phase comprises AND gates, with each independent signal unit having a pair of such gates, with one gate of such a pair being operative to effect actuation of the stop lights, and the other gate of such a pair being operative to effect actuation of the go lights of the associated signal unit.

4. A system according to claim 3, wherein said timing means and said gates are so connected that initiation of actuation of the stop lights of all signal units is effected by means of an output step of the timing means, and initiation of actuation of the go lights is effected by means of corresponding AND gates.

5. A system according to claim 3, wherein the stop lights of all signal units are actuated by respective AND gates, which in turn are placed in nonblocking condition by an impulse from an output step of the timing means, and actuated to blocking condition in response to actuation of a first phase-responsive switch means.

6. A system according to claim 3, wherein at least some of the AND gates forming logical linkages are three input gates.

7. A system according to claim 3, wherein at least some of the AND gates forming logical linkages are two input gates.

8. A system according to claim 3, wherein the phase-responsive switch means are bistable switches, the first phase-responsive switches being so arranged that all but an initially actuated switch are blocked during a transition change, and the second phase-responsive switches are controlled by the first phase-responsive switches and the last output step of the timing means.

9. A system according to claim 8, comprising in further combination, a plurality of connecting fields, the logical linkages associated with a respective signal phase having a connecting field operatively connecting the same with cooperable first phase-responsive switches, a connecting field connecting such linkages with cooperable second phase-responsive switches, and a connecting field connecting such linkages with said timing means, whereby operational and timing variations may be effected by changes in connections within the resPective connecting fields.

10. A system according to claim 1, wherein said first and second phase-responsive switch means are bistable switches, each having a preparing input, a triggering and resetting input, and an output, the outputs of respective first phase-responsive switches being connected to respective preparing inputs of the second phase-responsive switches, and the logical linkages for each signal phase comprise a group of two-input AND gates and an OR gate with each signal unit having a pair of such AND gates, one gate of such pair being operative to effect actuation of the stop light of such unit, and the other gate of such pair being operative to effect actuation of the go light of such unit, such group having an operational and timing variations may be effected by changes in connections within the respective shunting fields.

11. A system according to claim 10, wherein said timing means comprises a timing generator and a counter therefor, the latter having a plurality of outputs representing respective time intervals, an AND gate, one input of which is operatively connected to the output of the timing generator and the other input thereof being connected over a delay member to an output of the counter representing the last counting output, operative to block such gate when such last counting output is reached, said counter having a start input operatively connected to the outputs of the respective first phase-responsive switches over an OR gate and a monostable switch.

12. A system according to claim 11, wherein each preparing input of the first phase-responsive switches is connectible to receive preparing voltage for effecting a phase selection, and each triggering input is connected over an AND gate having an input connected to the timing generator, and another input connected to the last counting output of the counter over a delay member, said last counting output being connected to the triggering input of the second phase-responsive switches over a monostable switch.

13. A system according to claim 1, wherein said first phase-responsive switch means are adapted to be selectively actuated in response to the operation of a usual traffic system timer.

14. A system according to claim 1, wherein said first phase-responsive switch means are adapted to be selectively actuated in response to the operation of a program selection device in time or traffic dependence, for example, a computer.

15. A system according to claim 1, wherein such logical linkages for a respective signal phase each comprise a plurality of AND gates, equal in number to the number of different protective periods required for the go light associated with a signal phase, each of such AND gates linking a respective timing output of said timing means with a respective second phase-responsive switch means, and a further AND gate controllable by said first-mentioned AND gates and an associated first phase-responsive switch means, said last-mentioned gate being operatively connected to the go light associated with such signal phase.

16. A system according to claim 1, wherein such logical linkages for each respective signal phase comprise a plurality of three-input AND gates, each having one input connected to a selected output of the timing means, a second input connected to a selected second phase-responsive switch means, and a third input connected to a selected first phase-responsive switch means, and means for operatively connecting each of the outputs of said AND gates to the go light associated with such signal phase.